When the Graphite appearance is selected in System Preferences, contenteditable elements' focus rings should be graphite by default rather than blue.
Currently the default focus ring color comes from html4.css:
:focus {
outline: auto 3px #1f5ccf
}
This rule should change dynamically to match the selection in System Preferences.

Supporting Graphite well has not been a high priority lately, but I agree completely that this change would be a correct one. The system's focus ring color does change to a gray color when Graphite has been selected.